The GEPRC DarkStar25 is essentially the larger 2.5-inch version of the DarkStar22, designed around DJI’s O4 Wide and O4 Pro Air Units. Apart from the larger size, GEPRC has also improved a few smaller details. On paper, the DarkStar25 sounds like a very capable little cinewhoop, with solid specs, 4S power, and an effective soft-mounted camera system. However, during my review, I discovered a few issues that you should know about before buying one.
New to cinewhoops? Learn more in my buyer’s guide: https://oscarliang.com/cinewhoop/
Where to Buy
Get the DarkStar25 cinewhoop from:
GEPRC includes a fairly generous accessories package:
- Spare canopy
- Four spare propellers
- USB-A to USB-C cable
- Extra battery strap
- Extra battery pads
- Spare rubber grommets
- Spare screws and hardware
- Tool for installing the rubber grommets
- Manuals and wiring diagrams
- Stickers
Specifications
- Frame: GEP-DS25
- Bottom Plate Thickness: 2.5mm
- Wheelbase: 115mm
- Flight Controller: TAKER F722 35A 32-bit AIO
- MCU: STM32F722
- Gyro: ICM42688-P
- Firmware: GEPRC_F722_AIO
- Flash Memory: 16MB
- ESC: BLHeli_32 35A
- Motors: SPEEDX2 1404 4600KV
- Propellers: HQProp DT63MMX3 V2
- Battery Connector: XT30
- GPS: Optional GEP-M10 Nano
- FPV System: DJI O4 Pro / O4 Wide Air Unit
- Receiver: Onboard 2.4GHz ELRS
- Recommended Battery: 4S 700–850mAh LiPo/LiHV
- Claimed Flight Time: 6 minutes 20 seconds to 8 minutes 30 seconds with slow cruising
- Weight: 180g
Frame Design and First Impressions
At first glance, the DarkStar25 looks very similar to the DarkStar22, just bigger. The camera canopy is almost identical: the entire O4 Pro Air Unit and camera are housed inside, and the canopy is mounted to the drone using 5 rubber grommets. These soft-mount the camera and help reduce jello and vibration during flight.
However, on the DarkStar22, the canopy could occasionally pop off during crashes. GEPRC addressed this on the DarkStar25 by running screws through two of the middle dampers. This means the canopy still benefits from soft mounting, but it is much less likely to separate from the frame in a crash.
The DarkStar25 is compatible with both the DJI O4 Pro and O4 Wide Air Units. I tested it with the DJI O4 Pro.
The prop guards appear to use a similar design to the Cinebot25 V2. The bottom plate is made from 2.5mm thick carbon fibre.
Not only are the propellers larger, but the DarkStar25 also uses bigger and more powerful 1404 motors together with a 4S battery, making it a substantially more powerful machine overall.
Not Easy to Take Apart
Avoid taking the DarkStar25 apart unless you really need to, because putting it back together is not particularly easy.
The rubber grommets are a pain to install. Even with the included needle-threading tool, it takes a lot of patience and time. Personally, I did not find the supplied tool particularly helpful.
When I reviewed the DeepSpace Dino20, it came with a small pair of plastic tweezers that worked extremely well for pulling these tiny grommets through narrow gaps in the frame. I think GEPRC should consider supplying something similar.
Also note that the DarkStar25 uses two uncommon 4.5mm hex nuts to secure the middle two grommets. Do not lose them, because there are no spares included. If you do lose one, you may have to resort to using zip ties.
Once I had the quad apart, though, I was impressed by how clean the construction is. The wires going to the O4 air unit, camera, antenna, and motors are neatly organised, which should make repairs and troubleshooting easier.
Electronics
The flight controller has a solid feature set and includes most of the modern functionality I would expect in a cinewhoop. The FC’s USB-C port is buried inside the frame, but GEPRC has thoughtfully added an extension that makes it accessible from the bottom of the quad.
However, there is no dedicated physical buzzer. Instead, the quad relies on the motors for beeping.
Thankfully, the motors are powerful enough that the beeping can still be heard from roughly 10 metres away, which should make a crashed quad a little easier to locate. Still, I would have preferred a proper buzzer.
There is also an LED strip running around the prop guards. It appears to be a single-colour LED strip (mine is red), and it is not addressable RGB. You cannot change its colour or control it directly through Betaflight. You can only switch it on or off by assigning an AUX channel to the USER mode in the Modes tab.
The LED is mainly cosmetic, and it does look good at night. Personally, though, I do not think it is necessary. I would rather remove it to save a few grams, reduce cost, and potentially make it easier to stay below the 250g limit.
GPS Didn’t Work
I was pleased that my DarkStar25 came with GPS, but unfortunately, it did not work.
I left the quad powered on for 5 minutes on the ground, and it didn’t find any satellites. I then carried on with my testing, and during around an hour of flying, it still did not acquire a single satellite.
Something is clearly wrong, maybe configuration, bad soldering, incorrect wiring, or simply a faulty GPS module. I will investigate further and update the review when I know more.
Another potential concern is the GPS mounting position. It sits quite close to the O4 Air Unit antennas, which could potentially affect GPS reception.
The mount appears to accommodate GPS modules up to around 12mm wide. For good GPS of these size check out my recommendations here: https://oscarliang.com/gps-review/#For-Compact-Micro-Builds
If you mainly fly outdoors in open areas and want some protection against signal loss, GPS is definitely worth having. However, GPS Rescue is not configured in Betaflight by default, so you will need to set it up yourself and test it thoroughly before relying on it.
My Betaflight GPS Rescue guide is here: https://oscarliang.com/setup-gps-rescue-mode-betaflight/
Battery Options and Mounting
Most 2.5-inch cinewhoops mount the battery on top, but the DarkStar25 is the opposite. For cruising, you probably will not notice much difference in flight. My guess is that this design choice comes down to the way the O4 camera and canopy are soft-mounted. There simply is not enough room to mount the battery on top, so GEPRC has placed it underneath. This design choice has little to do with flight performance.
There is nothing fundamentally wrong with an underslung battery, but it does have a couple of disadvantages.
- First, it is harder to place the drone level on the ground for take-off.
- Second, the battery itself is more exposed during hard landings.
For this reason, GEPRC provides a carbon-fibre protection plate that sits underneath the battery. It also helps the quad sit more level on the ground. But the plate adds around 6g, if staying below 250g is important to you, you probably will not want to use it.
The battery strap is also fixed between two metal bars underneath the frame, which places a practical limit on battery width. I measured roughly 31mm of usable width (accounting for the battery strap as well). For reference, my LAVA 4S 850mAh battery only just fits.
This is worth checking if you intend to use unusually wide 4S packs, e.g. 4S 18650 Li-ion packs probably won’t fit.
Here are the batteries I’ve tested and worked well.
BetaFPV Lava 4S 850mAh 100C LiPo
Sub250 4S 720mAh 100C LiHV
Weight
For a 2.5-inch cinewhoop, the DarkStar25 is somewhere around the middle of the pack. It is neither particularly light nor excessively heavy.
Without a battery or battery-protection plate, mine weighs around 180.2g. If you install the carbon-fibre battery plate, add around another 5.6g.
For comparison, it is lighter than the Cinebot25 V2 at 219g and slightly lighter than the 3-inch Cinelog30 V3 at 190g.
There is certainly still room for improvement in terms of weight.
With batteries installed (wihtout battery protection plate), weight measured:
- 4S 720mAh LiHV: 247g
- 4S 850mAh LiPo: 274g
With the 720mAh LiHV pack, the quad only just stays below the 250g limit. Anything larger will push it over.
If you need to save a few more grams, removing the LED strip could also help. Or use lighter dipole antennas on the O4 Pro, or switch to the O4 Wide.
ESC Firmware
Like the Cinelog30 V3 and Cinebot25 V2 we reviewed previously, the Darkstar25 shares the same ESC firmware concern.
It uses BLHeli_32, which is now effectively discontinued. Even more concerning, the firmware version installed is not an official release but a prototype build (31.9.2). In my testing, it worked fine, but we cannot be sure whether there are bugs we don’t know about. And even if issues are discovered, they cannot be fixed since you can no longer update BLHeli_32 ESCs.
You can’t even change ESC settings in this version (the “Write Setup” button just grey out), I guess that’s why it’s stuck on the 24KHz PWM frequency setting and not using 48KHz which is smoother.
So far it hasn’t caused any problems, but as the person flying it, you should be aware of this limitation and decide whether you are comfortable with the risk.
Flight Performance
Power and Speed
The DarkStar25 hovers at around 30% throttle. Initially, the power felt fairly modest, but once you give it some throttle, it’s surprisingly fast for such a small cinewhoop.
Because the GPS was not working, I can only estimate top speed, which is around 120–130km/h. That is very fast for a 2.5-inch cinewhoop. Acceleration is also impressive as you can see in my flight video.
Freestyle Performance
The DarkStar25 can definitely freestyle.
It is extremely responsive—almost too responsive. Flips and rolls somehow felt faster than I am used to, even with the same rates I normally fly. It almost made me want to reduce my rates.
However, I noticed some instability during extreme manoeuvres, particularly when suddenly dropping the throttle to zero. The quad twitched around unpredictably.
I suspect much of this behaviour comes from the aerodynamics of the ducts rather than the PID tune itself.
The propellers may also be slightly too heavy for the motors to change RPM as quickly as required. Trying a lighter or lower-pitch prop may help. Increasing motor idle could potentially improve the behaviour as well, although that would probably make the quad feel more floaty.
Apart from this, the tune is actually very good. I was particularly impressed by how little propwash there is.
Image Quality
When the wind is light and you are cruising gently, the DarkStar25 is perfectly smooth.
However, when flying faster (over 50% throttle), and in windy conditions, I started seeing more vibration and shakiness in the goggles.
I suspect the rubber grommets are simply too soft. I noticed a similar issue with the Dino20 I recently reviewed, which also uses a similar soft-mounting implementation for the O4 camera.
That said, the soft mounting works extremely well for stabilised footage. Using either Gyroflow or RockSteady, I did not encounter any stabilisation problems, and most of the small bumps visible in the goggles can be smoothed out effectively in post.
Flight Time
I tested the DarkStar25 with two batteries:
- 4S 850mAh LiPo: around 5–6 minutes of mixed freestyle and cruising.
- 4S 720mAh LiHV: I was getting around 4.5–5 minutes.
You could probably push these numbers by roughly another minute if you only cruise gently.
Noise
The DarkStar25 is quite noisy. I could still hear it from around 150 metres away.
This is worth keeping in mind if you are specifically looking for a quiet cinewhoop for flying around people or noise-sensitive locations.
How to Setup
Firmware
- The flight controller (FC) board target is GEPRC_F722_AIO, and it comes preloaded with Betaflight firmware version 2025.12.2. For CLI Diff, see here.
- ESC Firmware: BLHeli_32 Proto: 31.9.2
- ELRS Receiver Firmware Target: GEPRC Nano 2.4GHz PA100 RX, firmware 3.4.2
DJI O4 Pro OSD Setup
Betaflight Setup
Manual:
Conclusion
If you want a smaller and quieter cinewhoop that can squeeze through tighter gaps, I would still consider the DarkStar22. And for relaxed cruising, the DarkStar22 is totally adequate.
However, if you want a much more powerful and significantly faster cinewhoop, the DarkStar25 is the more compelling option. It’s one of the fastest 2.5inch cinewhoop I’ve tested so far.
Get the DarkStar25 cinewhoop from:
The downside is weight. The DarkStar25 is very close to the 250g limit, so if staying under 250g matters to you, you have to be very careful with battery selection.
For a combination of cinematic and freestyle flying outdoor, though, I still think the Cinelog30 V3 remains the better all-round option.
It is smoother, handles wind better, and does not suffer from the same shakiness at higher speeds or windy conditions. It is not quite as explosive or fast as the DarkStar25, but it is not far behind. The Cinelog30 is also more efficient and gives you longer flight times for the same battery.
If I could give GEPRC one piece of advice for the next DarkStar25 revision, it would be to reduce the weight. I think getting the dry weight closer to 170g should be possible. Also, thinner ducts, similar to those used on the Cinelog30, might help reduce some of the undesirable behaviour during extreme manoeuvres. The trade-off, of course, is durability. The current design is robust and should handle crashes better than a lighter, thinner frame.
As it stands, the DarkStar25 is an impressively powerful little cinewhoop with excellent speed, good tuning, and effective O4 stabilisation, but its weight, ESC firmware limitations, GPS issue on my unit, and high-speed vibration prevent it from being an obvious choice for everyone.
